Improving SIRGAS Ionospheric Model
The IAG Sub-Commission 1.3b, SIRGAS (Sistema de Referencia Geocéntrico para las Américas), operates a service for computing regional ionospheric maps based on GNSS observations from its Continuously Operating Network (SIRGAS-CON). The ionospheric model us
- PDF / 856,994 Bytes
- 6 Pages / 595.276 x 790.866 pts Page_size
- 101 Downloads / 198 Views
37
C. Brunini, F. Azpilicueta, M. Gende, E. Camilion, and E. Gularte
Abstract
The IAG Sub-Commission 1.3b, SIRGAS (Sistema de Referencia Geoce´ntrico para las Ame´ricas), operates a service for computing regional ionospheric maps based on GNSS observations from its Continuously Operating Network (SIRGAS-CON). The ionospheric model used by SIRGAS (named La Plata Ionopsheric Model, LPIM), has continuously evolved from a “thin layer” simplification for computing the vTEC distribution to a formulation that approximates the electron density (ED) distributions of the E, F1, F2 and top-side ionospheric layers. This contribution presents the newest improvements in the model formulation and validates the obtained results by comparing the computed vTEC to experimental values provided by the ocean altimetry Jason 1 mission. Comparisons showed a small underestimation of the Jason 1 vTEC by about 1.3 TECu on average and rather small differences ranging from 0.5 to 3.4 TECu (at 95 % probability level). The results are encouraging given that comparisons were made in the open ocean regions (far away from the SIRGAS-CON stations). Keywords
Ionosphere GNSS SIRGAS
1
Introduction
Not long ago, the IAG Sub-Commission 1.3b called SIRGAS (Sistema de Referencia Geoce´ntrico para las Ame´ricas), i.e. the Regional Reference Frame for Central and South America, operates a service for computing regional ionospheric maps based on the GNSS observations
C. Brunini (*) F. Azpilicueta E. Camilion E. Gularte GESA, Facultad de Ciencias Astrono´micas y Geofı´sicas, Universidad Nacional de La Plata, Paseo del Bosque s/n, La Plata 1900, Argentina e-mail: [email protected] M. Gende GESA, Facultad de Ciencias Astrono´micas y Geofı´sicas, Universidad Nacional de La Plata, Paseo del Bosque s/n, La Plata 1900, Argentina Consejo Nacional de Investigaciones Cientı´ficas y Te´cnicas, Buenos Aires, Argentina
provided by its Continuously Operating Network (SIRGASCON) (Brunini et al. 2011a). Since 2008, a continuous time series of maps describing the vertical Total Electron Content (vTEC) distribution for the SIRGAS region, with time resolution of 1 h, is available at the SIRGAS web page (www. sirgas.org). As other vTEC maps computed within the geodetic community (e.g.: Herna´ndez-Pajarez et al. 2009), SIRGAS maps were originally based on the so called thin layer ionospheric model (Brunini et al. 2011b). According to this model, the vertical structure of the ionosphere (from about 50 to 1,000 km above the Earth´s surface), is approximated with a spherical shell of infinitesimal thickness with equivalent vTEC (located somewhere between 350 and 450 km height). Within this approximation, the satellite-to-receiver slant Total Electron Content (sTEC) is converted into an equivalent vTEC on the shell, by means of a geometrical mapping function that only depends on the satellite elevation and the
Z. Altamimi and X. Collilieux (eds.), Reference Frames for Applications in Geosciences, International Association of Geodesy Symposia 138, DOI 10.1
Data Loading...
